I. Field of the Invention
The present invention relates generally to the field of adhesive technology. More particularly, the invention involves an adhesive-based system to removably stick relatively flat articles on surfaces. The adhesive system includes a pressure-sensitive adhesive coated on both sides a central flat, flexible support scrim. The system is well suited to the removable installation of many types of articles having rough surface texture such as floor coverings, including, but not limited to, woven carpets having a natural fiber back such as cotton or jute or tufted carpets manufactured with synthetic primary and secondary back, which mimic natural fiber backs in texture, such as ActionBac (Trademark of Amoco Fabrics and Fibers). The invention also pertains to a method of making such a double-sided adhesive floor covering installation product which provides uniform continuous patterned adhesive surface on the scrim to accomplish high-shear adhesion with all types of broadloom carpets or others having backs of a relatively rough texture.
II. Related Art
The technique of employing double-sided or two-sided tapes is well known to the floor covering art. Such products have traditionally been applied at the joints or seams to secure mating sections together and to the under floor or substrate to obliterate visible seams. More recently, relatively wide double-sided adhesive tape-like products have been used to install new carpeting over existing floor coverings. One such product known as Sigaway.RTM., available from SIGA-AG of Schachen, Switzerland, enables the removable installation of vinyl floor coverings over a variety of substrates and the installation of new carpet over existing carpet. The material is characterized as a tape and uses a pre-dried, pressure-sensitive contact adhesive film. That adhesive application tape is preferably used to cover the entire area of the installation. One drawback, however, resides in the fact that the product has a low tolerance to moisture penetration (approximately 3.5 lbs./1,000 sq. ft.) and is generally suitable to adhere only relatively smooth surfaced materials to substrates such as foam-back carpets, vinyls or other relatively smooth-backed products.
It is also generally known to apply varying patterns of adhesive to both sides of a tape scrim substrate. Groshens (U.S. Pat. No. 4,732,800) depicts the application of a heat-fusible adhesive material to a surface using an engraved or embossed cylinder. Bayer, Jr. et al in U.S. Pat. No. 5,597,618 disclose the application of a pressure sensitive adhesive to a receiving surface such as a paper substrate in a manner in which the characteristic surface of the adhesive layer may be varied by varying the surface velocity of an application member relative to the velocity of the substrate. Sieber-Gadient (U.S. Pat. No. 4,702,948) discloses a two-sided, woven, self-adhesive tape in which each side may be provided with a different adhesion capability. This may be achieved, for example, by an unevenness in the weave of the support layer or scrim caused by the crossing warp and weft threads that leads to a discontinuous or partial adhesive coating on the lower side. A smoother, upper side is provided with a uniform layer of adhesive which, in turn, addresses the floor covering to be held in place. In this manner, the supporting fabric produces unevenness only on the bottom side to make the material more readily detachable from the floor than from the floor covering material adhered to the top side.
While the above techniques offer certain advancements with respect to the installation of floor coverings utilizing two-sided adhesive bearing tapes or similar materials, this success has largely been limited to relatively smooth-backed floor covering materials rather than improving the installation of floor coverings having relatively rough backs including woven, broadloom, doublebacked tufted or unitary back (tufted or woven) carpets. With respect to the woven carpets, weaving produces a very regular pattern of warp and woof yarns in which the warp yarn runs lengthwise and the woof yarn runs across the width of the carpet. This regular pattern generally constitutes the back of the carpet and while regular in pattern, it presents an irregular or rough textured surface due to the crossing of the threads. While the face yarns are typically made of synthetic yarns such as various nylons, polyesters, polyolefins, acrylics and rayon, the back yarns of woven carpets are usually natural fibers, generally cotton or jute. In manufacture, the face yarns are woven into the back yarns in such a manner that the interweaving causes an interlock which holds the entire structure together. The rough texture of the back remains in the finished carpets.
Although tufted carpets look similar to woven carpets, their construction is actually quite different. In tufted carpets, the face yarns are inserted into a ready-made backing where they are adhesively held in place, usually by a coating of latex adhesive. A second back, which may be woven jute, is normally applied as an overlayer giving the carpet the outward appearance of being woven. Of course, certain carpets may be made entirely of synthetic materials. For example, those produced by Amoco Fabrics and Fibers which feature a secondary back that looks just like jute, but is actually a synthetic material are sold under the trademark ActionBac.
Unitary backs are tufted or woven carpets having only one application of a very low filler content, latex or polymeric back coating, giving them a very rough textured backing with deep recesses. No secondary fabric is applied as in ActionBac, or other such carpets used widely in heavy traffic commercial installations.
All these carpet types share backing materials which are uneven in surface texture and, therefore, difficult to uniformly address with a layer of adhesive material, particularly when that material is found as a layer applied to a flexible support carrying glue-down adhesive material. Accordingly, there remains a definite need in the art to provide a two-sided adhesive carpet laying material that adequately accommodates the rough surfaces associated with typical carpet backs and which, at the same time, enables the installed carpet to be removed and replaced without the need for scraping or solvents with respect to the floor.
Accordingly, it is a primary object of the present invention to provide a two-sided floor covering adhesive system that successfully retains many types of carpet materials including those of a class having uneven or rough backing texture.
A further object of the present invention is to provide a two-sided floor covering adhesive system that is pressure-sensitive and is further characterized by highshear strength, yet can be peeled off most surfaces unaided (without scraping).
Another object of the present invention is to provide a two-sided floor covering adhesive system that can be applied in a variety of widths and patterns to accommodate carpet rolls of varying widths and a variety of room sizes with or without seams.
A still further object of the present invention is to provide a two-sided floor covering adhesive system that provides an amount of adhesive on both sides of a flexible support scrim in troweled patterns.
A yet still further object of the present invention is to provide a two-sided floor covering adhesive system that is permeable to water vapor and so has relatively low sensitivity to floor moisture seepage.
Yet another object of the present invention is to provide a two-sided floor covering adhesive system that permits immediate occupancy upon floor covering installation.
Still another object of the present invention is to provide a two-sided floor covering adhesive system that contains no organic solvents (VoCs), is odor free and which can be utilized indoors in a commercial setting even on a work day.
Yet still another object of the present invention is to provide a method of making a two-sided floor covering adhesive system that includes application of a pressure-sensitive adhesive material to both sides of a flexible support scrim and curing the adhesive in situ on the scrim.
An additional object of the present invention is to provide a method of making a two-sided pressure-sensitive floor covering adhesive system that includes the application of the adhesive material on both sides of a flexible support scrim in desired troweled patterns.
Other objects and advantages will become apparent to those skilled in the art as they become familiar with the specification, drawings and claims herein.